It is not possible to insert a table or use any of the buttons for color, images, etc.

For the HTML text editor (insert tables) and such to work, you must allow e.g. VB script and javascipt run.
The easiest way is to add http: //yourstore.xx as a 'reliable' site

Internet Explorer >> tools >> internet options >> security >> trusted locations >> Locations >> add and type http: // your store.

Then much more should work as it should. Bl.a. you see 'OK' when you insert a table.